Recently, various types of driver convenience equipment have been developed, and particularly, an auto cruise controller has already become common and has been mounted in the most vehicles.
The auto cruise controller allows a vehicle to follow a set target speed even in a state in which the driving of an accelerator pedal by a driver is not performed, when the vehicle drives on a highway or the like.
Particularly, when the vehicle drives on uphill road while driving in a constant speed at the set target speed, the auto cruise controller follows the target speed by performing an acceleration control in which an amount of air and an amount of fuel are additionally compensated.
In addition, when the vehicle drives on a downhill road while driving in the constant speed at the set target speed, since the speed of vehicle exceeds the target speed due to acceleration by acceleration of gravity, the auto cruise controller performs a speed limitation through a control of an engine output torque. Here, in a case in which the vehicle does not follow the target speed in spite of the limitation of the engine output torque, the auto cruise controller follows the target speed by performing a brake control or performing a transmission control.
Meanwhile, the vehicle often limits torque of a driving apparatus. For example, the torque of the driving apparatus is limited in various cases such as an available power limiting situation, overheating, a low battery, and the like.
When the torque limiting situation described above is released, since the auto cruise controller according to the related art generates a large torque command in order to increase a current speed of the vehicle up to the target speed, there is problem that the auto cruise controller is hard on a driving system of the vehicle or causes the driver to feel uncomfortable ride comport.